FED-1728 Migrate to null safety

.github/workflows/dart_ci.yml

@@ -35,7 +35,7 @@ jobs:
         if: always() && steps.install.outcome == 'success'
 
       - name: Verify formatting
-        run: dart format --output=none --line-length=120 --set-exit-if-changed .
+        run: dart run dart_dev format --check
         if: ${{ matrix.sdk == '2.18.7' }}
 
       - name: Analyze project source
@@ -44,12 +44,20 @@ jobs:
 
       - name: Run tests (DDC)
         run: |
-          if [ ${{ matrix.sdk }} = '2.13.4' ]; then dart run build_runner test -- --preset dartdevc-legacy; else dart run build_runner test -- --preset dartdevc; fi
+          if [ ${{ matrix.sdk }} = '2.13.4' ]; then 
+            dart run build_runner test --delete-conflicting-outputs -- --preset dartdevc-legacy
+          else 
+            dart run build_runner test --delete-conflicting-outputs -- --preset dartdevc
+          fi
         if: always() && steps.install.outcome == 'success'
         timeout-minutes: 5
 
       - name: Run tests (dart2js)
         run: |
-          if [ ${{ matrix.sdk }} = '2.13.4' ]; then dart run build_runner test -- --preset dart2js-legacy; else dart run build_runner test -- --preset dart2js; fi
+          if [ ${{ matrix.sdk }} = '2.13.4' ]; then
+            dart run build_runner test --delete-conflicting-outputs --release -- --preset dart2js-legacy
+          else 
+            dart run build_runner test --delete-conflicting-outputs --release -- --preset dart2js
+          fi
         if: always() && steps.install.outcome == 'success'
         timeout-minutes: 5

CHANGELOG.md

@@ -22,8 +22,7 @@
     - markChildrenValidated
 
 #### Other API breakages
-- ReducerHook and StateHook have no public constructors and can no longer be extended
-- Ref.fromJs is now a factory constructor, meaning the Ref class can no longer be extended
+- `ReducerHook`, `StateHook`, and `Ref` are now `@sealed` and may not be inherited from
 - ReactComponentFactoryProxy.call and .build return type changed from dynamic to ReactElement
     - This matches the type returned from `build` for all subclasses, which is what’s returned by call, and reflects the type returned at runtime
     - Has potential to cause some static analysis issues, but for the most part should not affect anything since ReactElement is typically treated as an opaque type
@@ -37,8 +36,39 @@
 - ReactComponentFactoryProxy no longer `implements Function`
     - This should not be a breakage, since as of Dart 2.0 inheriting from Function has had no effect
 
-#### Potential behavior breakages
-- Component and Component2 members `props`/`state`/`jsThis` are late, will now throw instead of being null if accessed before initialized (e.g., in a constructor, final class field, or static lifecycle method).
+#### Behavior breakages unlikely to cause issues
+- Component and Component2 members `props`/`state`/`jsThis` are now [late](https://dart.dev/language/variables#late-variables), and will now throw instead of being null if accessed before initialized.
+
+    It should be very uncommon for components to be affected by this change, and any affected components are likely doing something wrong to begin with. 
+
+    These fields are only uninitialized:
+     - for mounting component instances: 
+        - in component class constructors (which we don't encourage)
+        - in component class field initializers (except for lazy `late` ones)
+     - in "static" lifecycle methods like `getDerivedStateFromProps` and `defaultProps`
+
+    Examples of code affected:
+    ```dart
+    class FooComponent extends Component2 {
+      // `props` would have always been null when this is initialized, but in 7.0.0 accessing it throws.
+      final something = (props ?? {})['something'];
+
+      // We strongly discourage declaring Dart constructors in component classes;
+      // for initialization logic, use componentDidMount instead. 
+      FooComponent() {
+        // `props` would have always been null here, but in 7.0.0 accessing it throws.
+        print(props);
+      }
+
+      @override
+      getDerivedStateFromProps(nextProps, prevState)  {
+        // `props` would have always been null here, but in 7.0.0 accessing it throws.
+        print(props);
+        return {};
+      }
+    }
+    ```
+
 
 ## [6.2.1](https://github.com/Workiva/react-dart/compare/6.2.0...6.2.1)
 - [#366] Fix lints and eliminate most implicit casts 

analysis_options.yaml

@@ -2,8 +2,7 @@ include: package:workiva_analysis_options/v2.recommended.yaml
 
 analyzer:
   strong-mode:
-    # TODO change to false as part of the null safety major, which avoids us having to add a lot more casts
-    implicit-casts: true
+    implicit-casts: false
   errors:
     must_call_super: error
     comment_references: info

build.yaml

@@ -1,11 +1,10 @@
 targets:
   $default:
     builders:
-      # mockito's builder is expensive and is not needed until this package is
-      # migrated to null-safety. At that point, it should be scoped only to
-      # relevant files.
       mockito:mockBuilder:
-        enabled: false
+        # Scope only to files declaring mocks, for performance.
+        generate_for:
+          - test/mockito.dart
       build_web_compilers|entrypoint:
         # These are globs for the entrypoints you want to compile.
         generate_for:

example/js_components/js_components.dart

@@ -18,7 +18,7 @@ main() {
 var IndexComponent = react.registerComponent2(() => _IndexComponent());
 
 class _IndexComponent extends react.Component2 {
-  SimpleCustomComponent simpleRef;
+  SimpleCustomComponent? simpleRef;
 
   @override
   get initialState => {
@@ -35,7 +35,7 @@ class _IndexComponent extends react.Component2 {
     setState({
       'open': true,
     });
-    print(simpleRef.getFoo());
+    print(simpleRef!.getFoo());
   }
 
   @override

example/test/function_component_test.dart

@@ -240,7 +240,7 @@ UseRefTestComponent(Map props) {
   return react.Fragment({}, [
     react.p({'key': 'urtKey1'}, ['Current Input: ${inputValue.value}, Previous Input: ${prevInputValueRef.current}']),
     react.input({'key': 'urtKey2', 'ref': inputRef}),
-    react.button({'key': 'urtKey3', 'onClick': (_) => inputValue.set(inputRef.current.value)}, ['Update']),
+    react.button({'key': 'urtKey3', 'onClick': (_) => inputValue.set(inputRef.current!.value!)}, ['Update']),
   ]);
 }
 
@@ -338,13 +338,13 @@ class FancyInputApi {
 }
 
 final FancyInput = react.forwardRef2((props, ref) {
-  final inputRef = useRef();
+  final inputRef = useRef<InputElement>();
 
   useImperativeHandle(
     ref,
     () {
       print('FancyInput: useImperativeHandle re-assigns ref.current');
-      return FancyInputApi(() => inputRef.current.focus());
+      return FancyInputApi(() => inputRef.current!.focus());
     },
 
     /// Because the return value of createHandle never changes, it is not necessary for ref.current
@@ -377,14 +377,14 @@ UseImperativeHandleTestComponent(Map props) {
     if (!RegExp(r'^[a-zA-Z]+$').hasMatch(city.value)) {
       message.set('Invalid form!');
       error.set('city');
-      cityRef.current.focus();
+      cityRef.current!.focus();
       return;
     }
 
     if (!RegExp(r'^[a-zA-Z]+$').hasMatch(state.value)) {
       message.set('Invalid form!');
       error.set('state');
-      stateRef.current.focus();
+      stateRef.current!.focus();
       return;
     }
 
@@ -453,13 +453,13 @@ UseImperativeHandleTestComponent2(Map props) {
     }, []),
     react.button({
       'key': 'button1',
-      'onClick': (_) => fancyCounterRef.current['increment'](),
+      'onClick': (_) => fancyCounterRef.current!['increment'](),
     }, [
       'Increment by ${diff.value}'
     ]),
     react.button({
       'key': 'button2',
-      'onClick': (_) => fancyCounterRef.current['decrement'](),
+      'onClick': (_) => fancyCounterRef.current!['decrement'](),
     }, [
       'Decrement by ${diff.value}'
     ]),

example/test/react_test_components.dart

@@ -87,7 +87,7 @@ class _CheckBoxComponent extends react.Component {
 var checkBoxComponent = react.registerComponent(() => _CheckBoxComponent());
 
 class _ClockComponent extends react.Component {
-  Timer timer;
+  late Timer timer;
 
   @override
   getInitialState() => {'secondsElapsed': 0};
@@ -169,7 +169,7 @@ class _ListComponent extends react.Component {
   @override
   render() {
     final items = [];
-    for (final item in state['items']) {
+    for (final item in state['items'] as List) {
       items.add(react.li({'key': item}, '$item'));
     }
 
@@ -297,7 +297,7 @@ int calculateChangedBits(currentValue, nextValue) {
 var TestNewContext = react.createContext<Map>({'renderCount': 0}, calculateChangedBits);
 
 class _NewContextProviderComponent extends react.Component2 {
-  _NewContextRefComponent componentRef;
+  _NewContextRefComponent? componentRef;
 
   @override
   get initialState => {'renderCount': 0, 'complexMap': false};
@@ -448,7 +448,7 @@ class _Component2TestComponent extends react.Component2 with react.TypedSnapshot
   }
 
   @override
-  componentDidUpdate(prevProps, prevState, [String snapshot]) {
+  componentDidUpdate(prevProps, prevState, [String? snapshot]) {
     if (snapshot != null) {
       print('Updated DOM and $snapshot');
       return;
@@ -473,7 +473,7 @@ class _Component2TestComponent extends react.Component2 with react.TypedSnapshot
     // Used to generate unique keys even when the list contains duplicate items
     final itemCounts = <dynamic, int>{};
     final items = [];
-    for (final item in state['items']) {
+    for (final item in state['items'] as List) {
       final count = itemCounts[item] = (itemCounts[item] ?? 0) + 1;
       items.add(react.li({'key': 'c2-$item-$count'}, '$item'));
     }
@@ -519,20 +519,20 @@ class _ErrorComponent extends react.Component2 {
 var ErrorComponent = react.registerComponent(() => _ErrorComponent());
 
 class _CustomException implements Exception {
-  int code;
-  String message;
-  String randomMessage;
+  final int code;
+  final String message;
+  final String randomMessage;
 
-  _CustomException(this.message, this.code) {
+  _CustomException(this.message, this.code) : randomMessage = _getRandomMessage(code);
+
+  static String _getRandomMessage(code) {
     switch (code) {
       case 1:
-        randomMessage = 'The code is a 1';
-        break;
+        return 'The code is a 1';
       case 2:
-        randomMessage = 'The Code is a 2';
-        break;
+        return 'The Code is a 2';
       default:
-        randomMessage = 'Default Error Code';
+        return 'Default Error Code';
     }
   }
 }

example/test/ref_test.dart

@@ -3,7 +3,6 @@ import 'dart:html';
 
 import 'package:react/react.dart' as react;
 import 'package:react/react_dom.dart' as react_dom;
-import 'package:react/react_client.dart';
 
 var ChildComponent = react.registerComponent(() => _ChildComponent());
 
@@ -85,36 +84,36 @@ class _ParentComponent extends react.Component {
   }
 
   // Callback refs
-  InputElement _inputCallbackRef;
-  _ChildComponent _childCallbackRef;
+  InputElement? _inputCallbackRef;
+  _ChildComponent? _childCallbackRef;
   showInputCallbackRefValue(_) {
     final input = react_dom.findDOMNode(_inputCallbackRef) as InputElement;
     print(input.value);
   }
 
   showChildCallbackRefValue(_) {
-    print(_childCallbackRef.somevalue);
+    print(_childCallbackRef!.somevalue);
   }
 
   incrementChildCallbackRefValue(_) {
-    _childCallbackRef.incrementValue();
+    _childCallbackRef!.incrementValue();
   }
 
   // Create refs
-  final Ref<InputElement> _inputCreateRef = react.createRef();
-  final Ref<_ChildComponent> _childCreateRef = react.createRef();
+  final _inputCreateRef = react.createRef<InputElement>();
+  final _childCreateRef = react.createRef<_ChildComponent>();
 
   showInputCreateRefValue(_) {
     final input = react_dom.findDOMNode(_inputCreateRef.current) as InputElement;
     print(input.value);
   }
 
   showChildCreateRefValue(_) {
-    print(_childCreateRef.current.somevalue);
+    print(_childCreateRef.current!.somevalue);
   }
 
   incrementChildCreateRefValue(_) {
-    _childCreateRef.current.incrementValue();
+    _childCreateRef.current!.incrementValue();
   }
 
   @override

example/test/speed_test.dart

@@ -53,7 +53,7 @@ class _Hello extends react.Component {
   @override
   render() {
     timeprint('rendering start');
-    final data = props['data'];
+    final data = props['data'] as List;
     final children = [];
     for (final elem in data) {
       children.add(react.div({

example/test/unmount_test.dart

@@ -23,7 +23,7 @@ void main() {
   print('What');
   final mountedNode = querySelector('#content');
 
-  querySelector('#mount').onClick.listen((_) => react_dom.render(simpleComponent({}), mountedNode));
+  querySelector('#mount')!.onClick.listen((_) => react_dom.render(simpleComponent({}), mountedNode));
 
-  querySelector('#unmount').onClick.listen((_) => react_dom.unmountComponentAtNode(mountedNode));
+  querySelector('#unmount')!.onClick.listen((_) => react_dom.unmountComponentAtNode(mountedNode));
 }